ORIGINAL: RCKen
Collapsable antennas like this are next to impossible to fix once a section has pulled out. The best remedy is to simply replace the antenna with a new one. Simple, easy, and you can be assured that the range of the radio has not been compromised. You can get a new one from Tower Hobbies for $8.59.
[link]http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXH468&P=SM[/link]
It's not worth risking your plane over a suspect antenna. Get a new one and you'll know for sure that you're good to go.
Ken
Futaba sells the same replacement antenna under the Duratrax brand name for $2.40 less than the Futaba branded antenna. I replaced the antenna on my 7CAF with the Duratrax SKU, both units are physically identical and functionality is also the same.
http://www3.towerhobbies.com/cgi-bin...?&I=LXD188&P=7